There are a variety of millimeter wave/microwave devices, as for example traveling wave tubes (TWT's) which require high-energy product, low-temperature coefficient permanent magnet materials. In such devices, the air gap flux density must be maintained constant over a wide temperature range. Since the magnetizations of Alnico, hard ferrite and the available rare earth-cobalt permanent magnet materials decrease with increasing temperature, one must compensate in some way for the magnetization changes. One method involves shunting the flux in the room temperature range by the addition of external shims attached to the magnets. The shim is made from an alloy, usually 30 percent NiFe, which has a Curie temperature slightly above room temperature. Thus, as the temperature increases, less flux is shunted and the flux density in the gap is maintained constant. However, the placement of the compensating shunts is an expensive, tedious, manual process. The addition of the shunt is a significant cost item amounting to more than 10% of the magnet cost itself. Thus, there is a real need to provide intrinsically temperature stabilized permanent magnet materials.